Bug: `"pip"` cache having nothing installed leads to post-run error

Description:

I have this:

        runs-on: 'ubuntu-latest'
        steps:
            -   uses: actions/setup-python@v5
                with:
                    python-version: '3.10'
                    cache: 'pip'

Bumping python-version from '3.10' to '3.12', I am now getting this error during Post Run actions/setup-python@5:

Post job cleanup.
Error: Cache folder path is retrieved for pip but doesn't exist on disk: /home/runner/.cache/pip

Action version:

v5

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Tools version:

3.10.13 to 3.12.1

Expected behavior:

I expect setup-python to somehow not error itself.

Seemingly related issues:

• https://github.com/actions/setup-python/issues/653
• https://github.com/actions/setup-python/issues/436

Actual behavior:

Here is the output of Run actions/setup-python@v5

  with:
    python-version: 3.12
    cache: pip
    check-latest: false
    token: ***
    update-environment: true
    allow-prereleases: false
  env:
    ...
Installed versions
  Successfully set up CPython (3.12.1)
/opt/hostedtoolcache/Python/3.12.1/x64/bin/pip cache dir
/home/runner/.cache/pip
pip cache is not found

Here is the output of Post Run actions/setup-python@5:

Post job cleanup.
Error: Cache folder path is retrieved for pip but doesn't exist on disk: /home/runner/.cache/pip

Start with the actions/setup-python@v5 cache handling and reproduce the Ubuntu hosted-runner workflow shown in the issue using Python 3.12 and an empty pip cache. Trace the post-run cleanup after the log reports that /home/runner/.cache/pip is missing; done means this workflow completes without an error when nothing has been installed.